The only problem with calling the procedure, is TShiftState. I tried passing ssShift (as per D7 help files) just to fill the param gap, but D7 returns...
[Error] Unit1.pas(95): Incompatible types: 'TShiftState' and 'Enumeration'
[Error] Unit1.pas(95): Incompatible types: 'TMouseMoveEvent' and 'procedure, untyped pointer or untyped parameter'

Here's a sample program that I wrote. The program creates 10 checkboxes dynamically when you click on a button. Then, when you move your mouse over a checkbox, the MyMouseMove event handler determines which checkbox it is and adjusts its caption accordingly.